According to voter registration records, the district leans heavily Democratic – about 39 percent of those who have registered with a party are Democrats, compared with about 16 percent who are Republicans. There are 132 independents ,and the rest are unaffiliated.

The 4th District was a split district until the 2011 election, when its Republican assemblyman was redistricted into neighboring 3rd District.

The district is currently represented by Democratic Assemblyman Paul Moriarty, a media consultant from Turnersville who was first elected in 2005, and Assemblywoman Gabriela Mosquera of Blackwood, in her second term.
The unopposed GOP candidates are Kevin P. Murphy of Washington Township and Jack Nicholson of Clementon.